Proceedings of the Second Mediterranean Symposium on Marine

ASSESSMENT OF COASTAL ENVIRONMENTAL QUALITY BASED
ON LITTORAL COMMUNITY CARTOGRAPHY: METHODOLOGICAL
APPROACH
Xavier TORRAS, Susana PINEDO, Maria GARCIA, Luisa MANGIALAJO and Enric BALLESTEROS
Centre d’Estudis Avançats de Blanes, Acc. Cala Sant Francesc 14, 17300 Blanes, SPAIN
ABSTRACT
In this study we present a new methodology for monitoring water quality based on <strong>the</strong>
cartography <strong>of</strong> rocky benthic communities in <strong>the</strong> littoral zone. Littoral communities
thriving in <strong>the</strong> selected coast are cartographied from a small boat and <strong>the</strong> cartographic
information is transcribed to a GIS. With <strong>the</strong> use <strong>of</strong> spatial databases and geographic
information system technology (GIS) it is possible to know not only <strong>the</strong> distribution <strong>of</strong>
rocky benthic communities along <strong>the</strong> coast but also to obtain an environmental quality
index giving a “quality” value to every community. This index takes into account <strong>the</strong>
length <strong>of</strong> <strong>the</strong> coast covered by each community, a value <strong>of</strong> ecological quality <strong>of</strong> each
community obtained by expert judgement, and a correction by different parameters
o<strong>the</strong>r than water quality involved in <strong>the</strong> distribution <strong>of</strong> littoral communities (e.g. natural
or artificial substrate, type <strong>of</strong> coast) which has been obtained with an accurate study <strong>of</strong>
<strong>the</strong> distribution <strong>of</strong> littoral communities in reference zones. This index, named Ecological
Quality Ratio, fulfils <strong>the</strong> requirements <strong>of</strong> <strong>the</strong> Water Framework Directive. (2000/60/EC).
INTRODUCTION
Littoral benthic communities can be used as biological indicators <strong>of</strong> environmental
changes because (1) <strong>the</strong>y are exhaustively studied, at least in <strong>the</strong> Western
<strong>Mediterranean</strong> and o<strong>the</strong>r European coasts, (2) <strong>the</strong>y integrate <strong>the</strong> environmental changes
occurring in marine ecosystems, and (3) <strong>the</strong>y are strongly affected by pollution.
Amongst <strong>the</strong> organisms that can be used as bioindicators we can point up <strong>the</strong> seaweeds,
which have some species that are good indicators <strong>of</strong> <strong>the</strong> environmental quality (e.g.
Levine, 1984). There are some studies that show <strong>the</strong> effects <strong>of</strong> industrial and wastewater
discharges on <strong>the</strong> macroalgae, mainly regarding <strong>the</strong> Fucophyceae, characterized in
<strong>the</strong> <strong>Mediterranean</strong> Sea by <strong>the</strong> genus Cystoseira (e.g. Bellan Santini, 1968; Soltan et al.,
2001). According to Belsher (1977) pollution also affects some red algae, with <strong>the</strong>
disappearance <strong>of</strong> some species <strong>of</strong> Gelidiales and Rhodymeniales, and <strong>the</strong> regression <strong>of</strong>
some Ceramiales, Gigartinales and Cryptonemiales.
We have selected <strong>the</strong> communities <strong>of</strong> <strong>the</strong> littoral zone (mediolittoral and upper
infralittoral according to Pérès and Picard, 1964) as biological indicators <strong>of</strong> <strong>the</strong>
environmental quality <strong>of</strong> <strong>the</strong> coastal waters. The community <strong>of</strong> Cystoseira mediterranea
ACTES DU DEUXIEME SYMPOSIUM MEDITERRANEEN SUR LA VEGETATION MARINE (ATHENES, 12-13 DECEMBRE 2003)
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